/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.api.java.io;

import java.io.IOException;
import java.util.Iterator;

import org.apache.flink.api.common.io.GenericInputFormat;
import org.apache.flink.core.io.GenericInputSplit;
import org.apache.flink.util.SplittableIterator;


/**
 * An input format that generates data in parallel through a {@link SplittableIterator}.
 */
public class ParallelIteratorInputFormat<T> extends GenericInputFormat<T> {

	private static final long serialVersionUID = 1L;
	
	
	private final SplittableIterator<T> source;
	
	private transient Iterator<T> splitIterator;
	
	
	
	public ParallelIteratorInputFormat(SplittableIterator<T> iterator) {
		this.source = iterator;
	}
	
	@Override
	public void open(GenericInputSplit split) throws IOException {
		super.open(split);
		
		this.splitIterator = this.source.getSplit(split.getSplitNumber(), split.getTotalNumberOfSplits());
	}
	
	@Override
	public boolean reachedEnd() {
		return !this.splitIterator.hasNext();
	}

	@Override
	public T nextRecord(T reuse) {
		return this.splitIterator.next();
	}
}
